Current regulating system



Dec. 5, 1933. BROWN 1,937,869

CURRENT REGULATING SYSTEM Filed March 13, 1931 Patented Dec. 5, 1933 UNITED STA res PATENT OFFICE Cutler-Hammer, Inc., poratlon of Delaware Application March 13,

11 Claims.

This invention relates to the control of circuits by means of electron tubes.

It is well known that a gaseous electron. discharge tube having a. grid will conduct current 6 when a potential is applied to its main electrodes of such polarity that the anode is positive with respect to the cathode and if the grid potential is not too highly negative. If the grid is highly negative with respect to the cathode at the moment when current is supplied to the main electrodes no current can flow therebetween. By subsequent reduction of the negative grid potential, current flow is initiated. However, after current has started to flow between the main l5 electrodes, variations in the grid potential will have no further effect upon such current flow. In the co-pending application of Carroll Stansbury, Serial No. stress, filed February 27, 1930, it is shown how the flow of current between the main 1 electrodes of the tube may be delayed after the application oia suitable potential, by impressing upon the grid a transient potential which is negative with respect to the cathode and discharging said potential to a value which permits the 86 tube to conduct current after a certain lapse of time.

. The present invention has for one of its objects to provide improved means to increase this time interval.

80 Another. object is to provide means, whereby the rate of change in grid potential at the moment when the tube becomes conducting is relatively high, so as to produce an accurate controlling effect.

36 Another object of the invention is to provide for controlling the current supplied to a translating device for a definite time interval after the current has first been applied thereto. Another object is to provide for regulation of $0 the time interval during which current flows through the translating device.

Other objects and advantages will hereinafter appear. I p

In the accompanying drawing Fig. 1 illustrates one form of circuit control embodying my invention, while Fig. 2 illustrates a modification or the system in Fig. 1, but it will be understood that the same maybe applied in a variety of other ways.

In the drawing, L and I.- are respectively the positive and negative lines of a direct'current supply circuit, 1 is a translating devicewhich is to be supplied with current for a limited time, 2 is an electromagnetic relay, having a winding 3, an armature 4 and normally closed contacts 5. 6 is a gaseous electron discharge tube, having a cathode 7, an anode 8 and a grid 9. The

cathode 7 is connected to the line IF while the grid is connected to plate 11 of condenser 10, whose other plate 12 is connected in series with Milwaukee, Win, a cor- 1931. Serial No."522,202

a resistance 13 to the line LP. A continuously running motor 14 is connected between the lines L and L. It drives a rotating commutator 15 which intermittently closes a shunt circuit from condenser plate 11 through the commutator and an adjustable resistance 16 to condenser plate 12. The system further includes a spring biased push button switch 17 having normally closed contacts 19 and normally open contacts 18. The normally closed contacts 19 complete a circuit from line L to condenser plate 12 while the normally open contacts 18, when closed, complete a oircuit from line L through winding 3 and tube 6 to line L and a branch circuit irom line L through contacts 18 and 5 and translating device 1 to line 1?.

The operationof the device is as follows:

With the push button switch 17 in its normal position condenser plate 12 is connected to the positive line L through contacts 19. The plate 12 therefore assumes a positive potential and the opposite plate 11 and grid 9 a potential slightly positive with respect to the cathode 7. As the commutator 15 revolves, there is a periodic discharge current flowing iirom the plate 12 to plate 11 through the resistance 16 and the commutator 15, but the resistance 16 is suficiently high to insure that during the moment when the circuit is completed only a small part of the charge of the condenser leaks ofi. If it is desired to supply current to the translating device 1, push button switch 1'? is depressed thereby opening switch 19 and closingswitch' 18. A circuit is thus completed from line L through contacts 18 and 5 and through the translating device to line L.- Another circuit is completed from line L through contact 18 and coil 3 to the anode 8 or tube 6. When the switch 19 opens, the plate 12 of condenser 10 which formerly had the potential of the line L assumes the potential of line L. This causes a corresponding drop in potential of the plate 11 and the grid 9 so that the grid now becomes highly negative with respect to the cathode 'l. As long as the potential of plate 11 is negative, the tube cannot conduct any current and therefore the electro-magnetic switch 2 is not energized. As the commutator 15 revolves, it intermittently permits a discharge current to flow from condenser plate 12 to condenser plate 11 whenever the commutator completes the shunt circuit through the resistance 16, until ultimately the condenser is sufficiently discharged and thereby the negative potential on the grid 9 reduced to a value which permits current to flow through the tube 6, whereupon the electromagnetic switch 2 is energized, thus opening the contacts 5 and interrupting the current supplied to the translating device 1. Upon release of the push button switch 17, the condenser 10 is again charged as has been described and upon subsethe translating device 1 is again supplied with current for a predetermined length of time as described heretofore.

The time interval may be adjusted by varying the capacity of the condenser 10 or. the value of the adjustable resistance 16 or by varying the shaft of the motor with a number of commutators 15 and 15 each having a different number of segments and connect these selectively into the discharge circuit by a selector switch 20, depending upon the discharge time desired.

Ii. the commutator were omitted and the discharge period of the condenser regulated by the value of the resistance 16 alone, a very high resistance would be necessary. Furthermore, the rate of change of the potential on the grid would rapidly decrease with increasing discharge time. As a result the moment at which the tube responds would vary with slight variations in its characteristic. On the other hand, by producing intermitted discharges with the commutator, the value of the resistance can be held within reasonable limits and the rate of discharge at the moment of response of the tube may still be high, resulting in more accurate response and control of the time interval to be controlled.

What I claim as new and desire to secure by Letters Patent is:

1'. In combination, a current supply, an electron tube having a cathode and a grid, means to impress upon said grid a potential negative with respect to said cathode, means to impress the potential of said supply upon said tube, means for gradually reducing said grid potential, and means for periodically arresting the effect of said reducing means.

2. In combination, a current supply, a gaseous electron tube having a cathode and a grid, means to impress upon said grid a potential negative with respect to said cathode, means to impress the potential of said supply upon said tube, means for gradually reducing said grid potential, and means for periodically arresting the eflect of said reducing means.

- 3. In combination, a current supply, a gaseous electron tube having a cathode and a grid, energy storage means to impress upon said grid a potential negative with respect to said cathode, means to impress the potential of said supply upon said tube, means for gradually discharging said storage means, and means for periodically arresting the effect of said reducing means.

4. In combination, a current supply, a-gaseous electron tube having a cathode and a grid, energy storage means connected to said grid and adapted to impress thereupon a potential which is negative with respect to the cathode, and means including means to charge said energy storage means and to impress the potential of said supply upon said tube, means for gradually discharging said energy storage means, and

. means for periodically arresting theeflect of adapted to impress thereupon a potential nega- 'quent depression of the push button switch, 17.

tive with respect to the cathode, means to connect said tube to said supply, means for gradually discharging said storage means, and means for periodically arresting the eilect of said reducing means. r v v 6. In combination, a current supply, a. translating device, a gaseous electron tube having a cathode and a grid, means connected in circuit with said tube and adapted to control the current supplied to said translating device, an energy storage circuit connected to said grid and adapted to impressthereupon a potential negative with respect to the cathode, means to connect said tube tosaid supply, means for gradually discharging. said storage ,means, and means for periodically arresting the effect of said reducing means.

7. In combination, a current supply, an electron tube having a cathode and a grid, energy storage means to impress upon said grid 9. potential negative with respect to said cathode, means to impress the potential of. said supply upon said tube, a discharge resistance connected in shunt with said energy storage means, and a switch for periodically interrupting said shunt connection.

8. In combination, a current supply, a gaseous electron tube having a cathode and a grid, energy storage means to impress upon said grid a potential negative with respect to said cathode, means to impress the potential oi? said supply upon'said tube, a discharge resistance connected in shunt with said energy storage means, and

a switch for periodically interrupting said shunt connection.

9. In, combination, a current supply, a gaseous electron tube having a cathode and a grid, energy storage means connected to said grid and adapted to impress thereupon a potential which is negative with respect to the cathode, and means including'means to charge said energystorage meansand to impress the potential of said supply upon said tube, a discharge resistance connected in shunt with said energy storage means, and a switch for periodically interrupting said shunt connection.

'10. In combination, a current supply, a translating device, a gaseous electron tube having a cathode and a grid, means connected in circuit with said .tube and adapted to control the current supplied to said translating device, an energy storage circuit connected to said grid and adapted to impress thereupon a potential negative with respect to the cathode, means to connect said tube to said supply, means for gradually-discharging said storage means, and a switch for periodically interrupting the circuit of said last-mentioned means.

11. In combination, a current supply, a translating device, an electromagnetic relay for controlling the connection of said device to said supply, a gaseous electron tube in circuit with awinding of said relay and having a cathode and a grid, a switch for controlling the connection of said tube and said translating device to said supply, a condenser connected to said grid, circuit connections for normally charging said condenser and impressing a potential upon said grid which is negative with respect to said cathode to prevent current flow through said tube and to alternately discharge said condenser, and a commutator for periodically starting and interrupting said discharge.

GLENDON 0. BROWN. 

